The above-described process is highly complicated, and sometimes errors occur in each part of the process shown as (a), (b), (c), and (d) in the figure. These errors, for example, could include mistaking one thing for something else (a), making a misjudgment based on an unclear memory (b), inability to think sufficiently because of fatigue (c), and pushing the wrong switch (d), among others.

When too much information is received through the sensors and transmitted to the brain, various operations such as setting priorities, analogizing, and emphasizing, among others, are automatically conducted. On the other hand, actions are sometimes taken automatically without making any judgments when people are doing familiar work. In such cases, a person might take action that is different from the expectations of the system. Moreover, people sometimes go against the rules. For example, they omit the confirmation process when in a hurry or because it is too much trouble, or because no problems have occurred to date.

We should check our own behaviors to reduce human errors caused by individual characteristics. Moreover, work contents and the work environment should be improved so that errors would not occur easily. Furthermore, a backup system should be prepared so that major problems would not be caused even errors are made.